PECAM1 and neoplasm: The elevated levels of TIGAR in HTLV-1+ tumor cells also correlated with increased angiogenesis and infiltration of the tumor stroma and secondary tissues by murine endothelial progenitors (CD31/Flk1-positive cells); and 2 animals developed splenic hemangiomas associated with HTLV-1-induced T-cell lymphomas [53].